Interpretive Summary: The amount and composition of egg white proteins are important traits for the poultry layer industry. Ovoinhibitor and ovomucoid are major protein inhibitors that influence egg proteins. In this paper, the ovoinhibitor and ovomucoid genes were mapped to specific location on chicken chromosomes. This information will help determine if these genes account for differences in egg quality traits in elite chicken lines. If yes, then poultry breeders could utilize this information via genetic marker selection. Furthermore, the mapping of the genes extends the coverage of the chicken genetic map, and the amount of observed conservation between the human and chicken genomes, which helps in identifying other chicken genes by virtue of their human counterparts. This important information regarding genetic influence on egg quality traits would be of interest to poultry breeders and producers.

Technical Abstract:
Ovoinhibitor (OIH) and ovomucoid (OVM) are the major proteinase inhibitors constituting 1.5 and 11% of the total proteins in hen egg white, respectively. Although OVM exerts its antiprotease activity only against trypsin, OIH has a wide spectrum of inhibitory activity for other proteinases that occur in chicken egg white and blood plasma. They are functionally similar proteins and having multiple domains with a characteristic pattern of disulphide bridges. From the analysis of DNA sequences and the positions of exons and introns, it is thought that OVM and OIH evolved from a common primordial single-domain inhibitor. Furthermore, it has been proposal that OVM will be localized on chicken chromosomes 10-15, based on chromosome fractionation. However, their exact chromosomal locations are yet to be clarified. Therefore, in this study we performed the mapping of chicken OIH and OVM to specific chromosomes.